Of 0 XFO X'D^SHIXE. 
of, provided the fall of water be not great, a Lock, will fuffice, 
which is made up only of bars of wood called Rimers^ fee per= 
pendicularly to the bottom of the pafiage (which are more or lefs 
according to its breadth) and Lockrgates ^wt down between eve- 
ry two of them, or boards put athwart them, which will keep 
a head of water as well as the Turn-pike for the paflage of a Barge^ 
butmuft be all pulled up at its arrival, and the water let go till 
there is an abatement of the fall, before the boat may pafs either 
down or upwards ; which, with the ftream, is not without vio- 
lent precipitation ; and againft it, at many places, not without 
the help of a Capflain at Land ; and fomtimes neither of them 
without imminent danger. 
44. But where the declivity of the Channel^ and fall of wa- 
ter is fo great, that few barges could live in the pafiage of them, 
there we have Turn-pikes^ whereof there are three between Ox- 
fcrJ md Bercot ; one at 7/^9', ^nothe^^t S a nforJ^ and a third at 
Culham in the Smft-ditch^ which was cut at that time v^^hen the 
River was made navigable ; and are all thus contrived. Firft, 
there are placed a great pair of Folding doors ^ or Flood-gates o^ 
Timber crofs the r/W, that open againft the ftream and (liut with 
it, not fo as to come even in a ftraightline, but in obtufe angle ^ 
the betrer to rclift and bear the weight of the vrater^ which by how 
much the greater it is, by fo much the clofer are the g^ites prelTed ; 
in each of which Flood-gates there is a /luce to let the water 
through at pleafure , without opening the gates themfelves. 
Within thefe, there is a large fquare taken out of the river^ built 
up at each fide with Free-ftone, big enough to receive the largeft 
barge afloat ; and at the other end another pair of Flood-gates^ 
opening, and (liutting, and having /luCesWke the former. Which 
is the whole Fabricko^ 2 Turn-pike. 
45. Attheuppermoft pair of thefe gates the water is ftopt, 
which raifes it in the riz/er above, and gives the Veffils pafiage o- 
verthe fiallovys^ which when come to the Turn-pik§s^ the Sluces 
are firfi: opened, and the water let in to the fquare or inclofed 
fpace between the two pair of gates^ where it muft necefiarily 
rife (the lower gates being (liut) till at length it comes to be level 
withthe furfaceof the riz/er above : when this is done, the up- 
per fi:ream then making no fuch preflure on the^<2/e^ as before, 
they are eafily opened by two or three men^ and the Ve^lh let in 
Gg one 
